Question

A convex lens produces a real image m times the size of the object. What will be the distance of the object from the lens

• A. $\left(\frac{m+1}{m}\right)f$
• B. $(m-f)f$
• C. $\left(\frac{m-1}{m}\right)f$
• D. $\frac{m+1}{m-1}f$

Answer 1

The correct option is A $\left(\frac{m+1}{m}\right)f$

By using $m=\frac{f}{f+u}$ here $-m=\frac{(+f)}{(+f)+u}\Rightarrow -\frac{1}{m}=\frac{f+u}{f}=1+\frac{u}{f}=-\left(\frac{m+1}{m}\right)f$